Tunneling Devices Using Chemically Doped 2D Materials
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Solution Overview
Problem
Semiconductor devices, particularly tunneling field effect transistors (TFETs), face challenges in achieving high on-current levels and power efficiency due to their low on-current and high power consumption, which limits their performance in low-power applications.
Innovation Solution
The development of tunneling devices with a two-terminal structure using chemically doped two-dimensional materials, specifically P-type and N-type graphene layers separated by a tunnel barrier layer, which enhances tunneling current intensity and probability, and includes materials like hexagonal boron nitride and transition metal dichalcogenides to improve rectification characteristics and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a tunneling mechanism is used in TFET, then power consumption is reduced and off-current is lowered, but on-current decreases
Solution Approach 1:
The patent applies local quality by creating asymmetric doping concentrations in the semiconductor layers adjacent to the tunnel barrier. One side has heavy doping while the other has light doping, which creates favorable band alignment for band-to-band tunneling while maintaining high on-current through localized carrier concentration optimization.
Solution Approach 2:
The patent changes key parameters including doping concentrations (heavy vs light doping), layer thicknesses (thin tunnel barrier), and material composition to optimize both tunneling efficiency and on-current. The tunnel barrier thickness is specifically controlled to enable quantum tunneling while the doping parameters are adjusted to balance off-current suppression and on-current enhancement.
2Device complexity
If conventional TFET structure is used, then device complexity is reduced, but tunneling current intensity and probability are insufficient
Solution Approach 1:
The patent employs composite material structures combining different semiconductor materials with distinct bandgaps and effective masses. The tunnel barrier is formed from materials optimized for tunneling, while adjacent layers use materials with favorable band alignment, creating a composite structure that enhances tunneling probability without significant complexity increase.
Solution Approach 2:
The patent transitions from conventional planar junctions to a vertically stacked multi-layer structure with a thin tunnel barrier sandwiched between doped semiconductor layers. This dimensional reorganization creates a direct tunneling path perpendicular to the layers, increasing tunneling probability by eliminating lateral transport barriers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed tunneling devices exhibit increased on-current levels, rectification characteristics, and low power consumption, enabling efficient operation at low voltages without the need for gate electrodes, thus addressing the limitations of existing TFETs.
Implementation Method 1
Since a tunneling field effect transistor (TFET) uses a band-to-band tunneling mechanism, the TFET has a lower off-current, a higher on/off current ratio, and lower power consumption than a metal-oxide-semiconductor FET (MOSFET).
Data Source
AI summary
A tunneling device may include a tunnel barrier layer, a first material layer including a first conductivity type two-dimensional material on a first surface of the tunnel barrier layer and a second material layer including a second conductivity type two-dimensional material on a second surface of the tunnel barrier layer. The tunneling device may use a tunneling current through the tunnel barrier layer between the first material layer and the second material layer.